The effect of subcritical water treatment on the physicochemical properties and α‐glucosidase inhibitory activity of <i>Sargassum fusiforme</i> polysaccharides
Mengqing Zhang, Zhenna Zhang, Lichun Guo, Wei Zhao
Abstract
Summary In order to make full use of Sargassum fusiforme (S. fusiforme) , subcritical water treatment, an environmentally friendly method, was used to degrade polysaccharides to enhance their functional activity. Results revealed that average molecular weight decreased with increasing subcritical water treatment time or temperature. The depolymerisation kinetic was found to follow a first‐order kinetics model fitted to 1/ M t – 1/ M 0 = k • t . Structural characterisation exhibited that subcritical water treatment changed the molar ratio composition of monosaccharides, while the main functional groups of S. fusiforme polysaccharides did not change significantly. Rheological characterisation demonstrated that the three degraded polysaccharides displayed shear‐thinning behaviour and viscoelasticity. Except for natural polysaccharides, the α‐glucosidase inhibitory activity of the three degraded polysaccharides was superior to that of acarbose. Consequently, this study can provide scientific evidence for subcritical water treatment as a green and efficient method to prepare bioactive polysaccharides with low molecular weight.